This is an ancillary study to the Systolic Hypertension in the Elderly Program (SHEP). It presents plans for investigating the prevalence and prognostic value of subclinical atherosclerosis in the Pittsburgh SHEP cohort and a cohort of normotensive controls. Continued annual telephone follow-up of the remaining 178 SHEP participants and 168 controls is proposed. A final clinic visit will include measures of coronary and aortic calcification using electron beam computed tomography (CT), pulse wave velocity as a measure of aortic stiffening and cognitive function testing. For the Pittsburgh SHEP cohort, the antihypertensive treatment effect has been striking with event rates for the active and placebo groups continuing to diverge beyond the end of SHEP. Successful demonstration of a treatment effect on coronary calcium scores would be the first randomized data showing an antihypertensive effect directly in the coronary arteries. Risk factors for coronary calcification will be evaluated, producing data of a type not yet available in the literature for older adults and not being collected in any other ongoing studies of the elderly. The added measures of vascular stiffness will supplement the extensive data on subclinical atherosclerosis already available for this cohort. The extent to which these measures predict cardiovascular events will be evaluated. Since hypertension and aging are associated with cognitive impairment and vascular dementia, SHEP participants assigned to the placebo group are expected to have lower cognitive function compared to those assigned to active treatment. Among both hypertensive and normotensive groups, lower cognitive function among those with evidence of subclinical atherosclerosis is expected. Finally, members of the cohort who were originally normotensive at study entry are now developing systolic hypertension. These subjects will allow a prospective evaluation of risk factors for systolic hypertension. Continued study of this cohort into their 80s will provide unique data on the risks and etiology of systolic hypertension, the efficacy of its treatment and the prognostic value of a number of measures of subclinical atherosclerosis. It is predicted that the results will be directly applicable to the largest growing segment of the U.S. population.